<p>魔法值【%s】</p>
<p>不允许任何魔法值（即未经定义的常量）直接出现在代码中。</p>
<p>Examples:</p>
<pre>
    Negative example:
    //Magic values, except for predefined, are forbidden in coding.
    if (key.equals("Id#taobao_1")) {
            //...
    }
    Positive example:
        String KEY_PRE = "Id#taobao_1";  
        if (KEY_PRE.equals(key)) {
                //...
        }
</pre>